Dante? What the hell. It was the medieval world that insisted on infernal retribution, not ours. In the Divine Comedy - Dante's three-part journey through the inferno, purgatory and paradise - we imagine the state of souls after death. Some are boiled alive in brimstone, others glow with a heavenly grace.

The belief in eternal punishment probably strikes most people today as superstitious hocus-pocus. If the Divine Comedy speaks to our present condition, it is not because we are moved by the terror of the Christian revelation, or the threat of being barbecued in the seventh circle of hell for making too much money. Dante's 600-year- old poem remains one of the essential books of mankind despite our distance from medieval theology. As James Joyce proclaimed: 'I love Dante as much as the Bible. He is my spiritual food, the rest is ballast'.

Some still miss the whiff of sulphur, however, and fear that our public and private morality has gone to the devil without it. Only 22 months ago the Education Secretary, John Patten, subjected readers of the Spectator to this Dantean blast of hellfire: 'Dwindling belief in redemption and damnation has led to loss of fear of the eternal consequences of goodness and badness . . . The loss of that fear (eternal damnation) has meant a critical motive has been lost to young people when they decide whether to try to be good citizens or criminals.' Hell's bells] Our Education Secretary may or may not be man enough for damnation, but his remarks would be familiar to the Victorian reader of Dante.

In Victorian times Dante was a popular quarry for translators. John Ruskin hailed him 'the central intellect of the world' and his stupendous greatness was celebrated at Bible classes throughout the Empire. Civil servants, clergymen, barristers; they all had a go at Dante. That their translations were mostly dreadful (the crystalline cantos of Dante converted into galumphing fustian) scarcely mattered. There was a message for contemporary society in the Divine Comedy which these worthies saw it as their duty to convey. What happens to sinful love-cheats? To those who commit adultery? Look no further than the fifth canto of Hell (in part one of the Divine Comedy), where Paolo and Francesca are twisting in a black whirlpool without hope. If there was anyone who could take us back to the basics of damnation, it was Dante Alighieri from Florence.

So Dante became the saddest and most serious of poets, his trilogy translated with an austere literalism that ignored the vulgar energy of the original. Numerous Jesuit editions of Dante were crudely and thoroughly censored; and Victorian translators must have agonised, to say the least, over the scene from Hell (canto 21) where a military commander makes a trumpet of his arse by breaking musical wind. The Reverend Henry Boyd translated Dante's farts as 'loud Aeolian fifes' after the Greek god of wind. When William Burroughs's novel Naked Lunch was prosecuted for obscenity in 1965 (the notorious 'talking asshole' chapter), Dante was cited in its defence.

The Victorians turned not only Dante into a paragon of moral sobriety, but also the flame of his life: Beatrice Portinari. Not much is known about Beatrice, only that she died at Florence in 1290 and drove Dante to distraction. In the Divine Comedy itself, Beatrice is Divine Grace; she appears before the speechless Dante as a veiled woman in robes the colour of a 'living flame'. This was poetry enough. But the Pre-Raphaelite Brotherhood worshipped Beatrice as a blessed dewey-eyed damsel, tender as a marshmallow.

Though bowdlerised, the Divine Comedy became a Victorian bestseller. The only other post-classical work of comparable bulk translated on the same scale was Goethe's Faust. Longfellow and Carlyle (not Thomas Carlyle) gave the most successful versions of Dante, and made him a commercial proposition. But they both marred the original with their awful Latinate locutions and stilted choice of words; it was like drinking flat champagne.

Who put the fizz back into the Florentine? None other than Dorothy L Sayers, the detective novelist. Many who buy the Penguin Dante (published between 1949 and 1962) are surprised to find that the translator is the same Sayers who created the dandified sleuth Lord Peter Wimsey. Lord Peter's private collection of printed Dantes is certainly worth investigation; from Whose Body, we understand that it 'includes, besides the famous Aldine octavo of 1502, the Naples folio of 1477'. This bibliographic pedantry - fetishism, almost - squares with Sayers' own private obsession. The last 13 years of her life were devoted to a translation of Dante; and it was a wonderfully spirited version, mingling modern and archaic expressions, a sour wit curdling those honeyed hymns to Beatrice.

Since Dorothy L Sayers, Dante has had more English-speaking readers in the last 40 years than the preceeding six and a quarter centuries. Trimmed of the Victorian distortions, Dante is a rousing read. His journey to salvation in the Divine Comedy involves a descent to the centre of the earth, which is also the bottom of hell (medieval cartographists must have located this limbo somewhere in Australia); then follows a thorny climb to the summit of Mount Purgatory where Dante reaches the celestial sight of Beatrice and the mystical revelation of God in Paradise.

The Divine Comedy has passed like a runner's baton from generation to generation, changed and enriched. We can read it as an intoxicating adventure story, as a simple love story, as the story of anyone who sets out in search of salvation in this life. Primo Levi relates in If This is a Man how he struggled at Auschwitz to remember lines spoken by Dante's Ulysses:

Think of your breed; for brutish ignorance

Your mettle was not made; you were made men,

To follow after knowledge and excellence.

In the hell of Auschwitz - 'anus of the world' - this is one of the greatest hymns to literature and the human spirit ever written. For Primo Levi, Dante's poem was the first great step from Gothic darkness to the light of Renaissance humanism.

One inferno is enough, you might think. But here we have another translation of Dante's Hell (Chatto, pounds 14.99). Steve Ellis, a Senior Lecturer in English at Birmingham University, believes that the sulphurous poem has never been adequately translated; even Sayers has dated. If Dante is still a bit of a dodo, an endangered species from the groves of academe, part of the blame must lie with T S Eliot (says Ellis). In 1929 Eliot published an influential pamphlet that championed Dante as the highest expression of Christian civilisation.

The Florentine encouraged Eliot in his conviction that modern man is mired in a spiritual no man's land; but, like the Victorians, he ignored the less elevated aspects of Dante's poem. The vituperative satire, the vulgar burlesque, the harsh and grating rhymes - Eliot would have little of this. It was the austerity of Dante that appealed, the sour old lemon who bemoaned, from his lofty vantage point, the pain of living. 'I had not thought death had undone so many' we read of those rush-hour commuters in The Waste Land.

This new translation of Hell is a million miles from the Dante passed down to us by Eliot. It is a creative transformation. Energetic, racy, rude and lyrical, the version is above all demotic; words like 'tart', 'bonce', 'shite' and 'crap like this' move easily with the grain of Dante's speech, and sustain the stabbing beat of the original. Steve Ellis has wisely dispensed with Dante's terza rima - a fiendish triple rhyme - and used a very effective free verse instead.

There's just one problem. Ellis almost wrecks the package with his rendering of the famous opening line - 'Nel mezzo del cammin di nostra vita / mi ritrovai per una selva oscura' - as 'Halfway through our trek in life / I found myself in this dark wood'. Afrikaans for travel by ox-wagon, 'trek' also conjures an image of sports shoes. This is all wrong: we should enter the poem in a magical way. Dante is alone in a supernatural forest at nightfall, a pilgrim who has lost his way in mid-life. Virgil, sent by Beatrice, is about to show him hell. The Longfellow translation begins: 'Midway upon the journey of our life. . .' 'Journey' is a huge improvement.

The rest of Hell is a terrible delight. The further we climb down through inferno the more it seems that Dante was blessed with a mean disposition. Adulterers, prostitutes ('that tart Cleopatra'), homosexuals and all non-Christians (including the Prophet Mohammed) are banished to eternal damnation. Dante held politicians in particularly low esteem - colossal humbugs who had ruined his native Florence with their new money and slippery double-standards.

Nietzsche was wrong, though, to slander Dante as a hyena making verses among the tombs. The poet did more than simply put his mates in paradise and his foes in limbo. 'We must also be prepared to find Dante simple, homely, humorous, tender and bubbling over with ecstasy', enthused Dorothy L Sayers. Italian literature begins and ends with Dante; he is the great patriarch of modern letters. Buy this translation by Professor Ellis and spend a damn good season in hell.